At least 60 people have been killed in the town this year – and more than 500 others around the border area – all connected to a turf war between the drug dealers and the Mexican government of President Vicente Fox.

Enlisted into this war is a paramilitary group of commandos know as the Zetas, trained by the U.S. as drug fighters, but co-opted by the cartels as their personal army.

The U.S. State Department has singled out Nuevo Laredo in a recent advisory, warning travelers to use common sense when visiting Mexican border cities.

Oscar Mendoza Arriaga, a municipal police commandant, said Saturday’s shooting was the result of “confusion” because the federal agents weren’t in uniform. He said the federal agents were in the back of three pickup trucks, some with guns.

“So the police tried to do a routine check, but the people in the truck fired at them,” said Mendoza, who arrived at the scene of the shooting, which lasted a few minutes, after it was over. “The big problem is these people are federal.”

There were reports, however, that the municipal police fired first, according to the San Antonio Express-News.

Federal agents were reportedly sent to Nuevo Laredo in the wake of the brutal killing Wednesday night of Police Chief Alejandro Dominguez Coello, 54. The former president of the chamber of commerce, Dominguez had taken over as police chief just hours before he was shot.

Yesterday’s death brings the total number of dead officers in the town to eight so far this year.